/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.jbpm.bpmn2.xml;

import java.util.HashSet;
import java.util.Map;

import org.jbpm.bpmn2.core.Lane;
import org.jbpm.bpmn2.core.SequenceFlow;
import org.jbpm.compiler.xml.Handler;
import org.jbpm.compiler.xml.Parser;
import org.jbpm.compiler.xml.core.BaseAbstractHandler;
import org.jbpm.process.core.ValueObject;
import org.jbpm.process.core.context.variable.Variable;
import org.jbpm.process.core.datatype.DataType;
import org.jbpm.process.core.datatype.impl.type.StringDataType;
import org.jbpm.ruleflow.core.RuleFlowProcess;
import org.jbpm.workflow.core.Node;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

public class MetaDataHandler extends BaseAbstractHandler
        implements
        Handler {
    public MetaDataHandler() {
        if ((this.validParents == null) && (this.validPeers == null)) {
            this.validParents = new HashSet();
            this.validParents.add(Node.class);
            this.validParents.add(RuleFlowProcess.class);
            this.validParents.add(Variable.class);
            this.validParents.add(SequenceFlow.class);
            this.validParents.add(Lane.class);

            this.validPeers = new HashSet();
            this.validPeers.add(null);

            this.allowNesting = false;
        }
    }

    public Object start(final String uri,
            final String localName,
            final Attributes attrs,
            final Parser parser) throws SAXException {
        parser.startElementBuilder(localName,
                attrs);
        Object parent = parser.getParent();
        final String name = attrs.getValue("name");
        emptyAttributeCheck(localName, "name", name, parser);
        return new MetaDataWrapper(parent, name);
    }

    public Object end(final String uri,
            final String localName,
            final Parser parser) throws SAXException {
        parser.endElementBuilder();
        return null;
    }

    public Class generateNodeFor() {
        return MetaDataWrapper.class;
    }

    public class MetaDataWrapper implements ValueObject {
        private Object parent;
        private String name;

        public MetaDataWrapper(Object parent, String name) {
            this.parent = parent;
            this.name = name;
        }

        public Object getValue() {
            return getMetaData().get(name);
        }

        public void setValue(Object value) {
            getMetaData().put(name, value);
        }

        public Map<String, Object> getMetaData() {
            if (parent instanceof Node) {
                return ((Node) parent).getMetaData();
            } else if (parent instanceof RuleFlowProcess) {
                return ((RuleFlowProcess) parent).getMetaData();
            } else if (parent instanceof Variable) {
                return ((Variable) parent).getMetaData();
            } else if (parent instanceof SequenceFlow) {
                return ((SequenceFlow) parent).getMetaData();
            } else if (parent instanceof Lane) {
                return ((Lane) parent).getMetaData();
            } else {
                throw new IllegalArgumentException("Unknown parent " + parent);
            }
        }

        public DataType getType() {
            return new StringDataType();
        }

        public void setType(DataType type) {
        }
    }

}
